What chunky dogs and obese people have in common — and what it tells us about weight loss

Howl-lelujah!

Dogs and humans are fatter than ever — it’s no surprise that overweight people tend to have overweight dogs. Now, scientists from the University of Cambridge in the UK say they’ve identified why both groups are more likely to be husky, which may pave the way for treatment options.

The team found several genes linked to canine obesity while studying British Labrador retrievers. The gene with the strongest tie is DENND1B — humans also carry it.

DENND1B has been associated with an increased susceptibility to asthma, particularly in children. It also directly affects the leptin-melanocortin pathway, which plays a crucial role in regulating energy balance and body weight.

“The results emphasize the importance of fundamental brain pathways in controlling appetite and body weight,” said Alyce McClellan, a first author of the study, published Thursday in Science.

McClellan’s team analyzed the genetics of 241 retrievers by sampling their saliva. They measured each dog’s body fat and compared their obesity status to their DNA.

Dogs carrying DENND1B had about 8% more body fat than those without it.  

“Studying the dogs showed us something really powerful: Owners of slim dogs are not morally superior. The same is true of slim people,” said Dr. Eleanor Raffan, a University of Cambridge researcher who led the study.

“If you have a high genetic risk of obesity, then when there’s lots of food available you’re prone to overeating and gaining weight unless you put a huge effort into not doing so,” Raffan added.

Dogs at high genetic risk of obesity showed signs of a bigger appetite, which also has been seen in humans with the same elevated risk.

The good news is that Raffan and her colleagues found that owners who strictly managed their dogs’ diet and exercise prevented even those at high genetic risk from becoming obese.

The researchers recommend owners distract dogs from their constant hunger via portion control. Try scattering their food over a wide area so it takes longer to eat or select a more satisfying nutritious blend.

Similarly, people at high genetic risk of obesity can avoid weight gain if they follow a rigid diet and exercise regimen.

No one gene determined whether the dogs were prone to obesity — the high- or low-risk designation was the net effect of several genetic variants.

Four genes tied to canine obesity were found to exert a smaller effect than DENND1B. They were also mapped onto human genes.

“These genes are not immediately obvious targets for weight-loss drugs, because they control other key biological processes in the body that should not be interfered with,” McClellan said.

Raffan noted that dogs are genetically similar to humans, and they gain weight through comparable environmental influences. Other factors also make them a good model for studying human obesity.

“By studying dogs we could measure their desire for food separately to the control owners exerted over their dog’s diet and exercise,” Raffan said. “In human studies, it’s harder to study how genetically driven appetite requires greater willpower to remain slim, as both are affecting the one person.”